package com.trendata.util;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;

import com.trendata.domain.wechat.Config;

/**
 * 签名
 * 
 * @author: HuangXiuXiu Email:243559392@qq.com
 */
public class SignUtil {

	// 与接口配置信息中的Token要一致
	private static String token = "qushu";

	/**
	 * 验证签名
	 * 
	 * @param signature
	 * @param timestamp
	 * @param nonce
	 * @return
	 */
	public static boolean checkSignature(String signature, String timestamp, String nonce) {
		String[] arr = new String[] { token, timestamp, nonce };
		// 将token、timestamp、nonce三个参数进行字典序排序
		Arrays.sort(arr);
		StringBuilder content = new StringBuilder();
		for (int i = 0; i < arr.length; i++) {
			content.append(arr[i]);
		}
		MessageDigest md = null;
		String tmpStr = null;

		try {
			md = MessageDigest.getInstance("SHA-1");
			// 将三个参数字符串拼接成一个字符串进行sha1加密
			byte[] digest = md.digest(content.toString().getBytes());
			tmpStr = byteToStr(digest);
		} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
		}

		content = null;
		// 将sha1加密后的字符串可与signature对比，标识该请求来源于微信
		return tmpStr != null ? tmpStr.equals(signature.toUpperCase()) : false;
	}

	/**
	 * 获取jssdk验证
	 * 
	 * @param url
	 *            使用该验证的url地址
	 * @param ticket
	 *            jssdkTicket
	 * @return
	 */
	public static Config getSignature(String url, String ticket) {
		String nonceStr = getNonceStr();
		String timestamp = getTimeStamp();
		// 字典排序的签名参数
		String string1 = "jsapi_ticket=%s&noncestr=%s&timestamp=%s&url=%s";
		string1 = String.format(string1, ticket, nonceStr, timestamp, url);
		// 对string1进行sha1签名，得到signature
		String signature = md5(string1).toLowerCase();
		// 最后组装json数据
		Config config = new Config();
		config.setAppId(Constants.APP_ID);
		config.setTicket(ticket);
		config.setNonceStr(nonceStr);
		config.setSignature(signature);
		config.setTimestamp(timestamp);
		return config;
	}

	/**
	 * md5加密
	 * 
	 * @param string
	 */
	private static String md5(String string) {
		String tmpStr = null;
		MessageDigest md = null;
		try {
			md = MessageDigest.getInstance("SHA-1");
			byte[] digest = md.digest(string.getBytes());
			tmpStr = byteToStr(digest);
		} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
		}
		return tmpStr;
	}

	/**
	 * 获取随机字串（16位）
	 * 
	 * @return
	 */
	private static String getNonceStr() {
		String nonce_str = "";
		String chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
		int maxPos = chars.length();
		for (int i = 0; i < 16; i++) {
			nonce_str += chars.charAt((int) Math.floor(Math.random() * maxPos));
		}
		return nonce_str;
	}

	/**
	 * 获取时间戳
	 * 
	 * @return
	 */
	private static String getTimeStamp() {
		return String.valueOf(System.currentTimeMillis() / 1000);
	}

	/**
	 * 将字节数组转换为十六进制字符串
	 * 
	 * @param byteArray
	 * @return
	 */
	private static String byteToStr(byte[] byteArray) {
		String strDigest = "";
		for (int i = 0; i < byteArray.length; i++) {
			strDigest += byteToHexStr(byteArray[i]);
		}
		return strDigest;
	}

	/**
	 * 将字节转换为十六进制字符串
	 * 
	 * @param mByte
	 * @return
	 */
	private static String byteToHexStr(byte mByte) {
		char[] Digit = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
		char[] tempArr = new char[2];
		tempArr[0] = Digit[(mByte >>> 4) & 0X0F];
		tempArr[1] = Digit[mByte & 0X0F];

		String s = new String(tempArr);
		return s;
	}

}
